Speed Permanent Magnet Synchronous Machine Research Articles

A New Rotor Structure for High Speed Flywheel Permanent Magnet Synchronous Machine

This paper presents a new rotor design with assembled permeable retaining sleeve (APRS) to improve performances of a high speed permanent magnet synchronous machine (PMSM). The APRS consists of equal number of permeable and nonmagnetic parts, which are alternately arranged and assembled together circumferentially via keyways. Electromagnetic and mechanical characteristics of the rotor applied to a high speed flywheel PMSM are analyzed using finite element method. Machine performances are compared to an original design with commonly used rotor structure. It shows that phase inductance of the high speed machine increases dramatically due to smaller effective air gap, which may benefit suppressing inverter current harmonics. Also, permanent magnet usage reduces by 9.4 % to obtain identical back electromotive force and torque constant. In addition, a smaller skin depth owing to high-permeability material and the circumferential segmentation of the retaining sleeve effectively reduce rotor eddy current. Associated loss decreases by 40.7 % under open-circuit condition. A prototype rotor is fabricated and preliminary experimental tests are performed to confirm the analysis results.

Next‐generation integrated drive: A high power density permanent magnet synchronous drive with flooded stator cooling

The next-generation integrated drive (NGID) is an 80 kW demonstrator showcasing the latest innovations in high power density electric drive technology. A prototype 30 krpm maximum speed permanent magnet synchronous machine for an automotive traction application is under construction. This study describes several aspects of the detailed design and how these fit together in the complete drive package to increase the power density of the NGID.

Torque Ripple Reduction of PMSMs Using a Novel Angle-Based Repetitive Observer

The angle-based repetitive controller (RC) has been applied successfully in the literature for torque ripple suppression in variable speed permanent magnet synchronous machines (PMSMs). The RC is preferred because of its learning capability, which allows the cancelation of all periodic ripples from multiple sources. However, its tuning method has not yet been proposed. Since the structure of the RC is found similar to the disturbance observer (DOB), which is convenient to tune through pole placement, this paper merges the angle-based RC and DOB into a novel angle-based repetitive observer (ARO) for the first time for the torque ripple reduction in PMSMs. ARO takes advantages of its DOB structure that it can be designed separately and can easily be added into an existing control loop. Taking advantage of its RC nature, ARO can tackle a wide frequency range of torque ripple even in the presence of measurement noise. The experimental test results have confirmed the robust performance of ARO under five conditions, including the ideal integral delay, the fractional delay, the load transient, the speed transient, and the detuned mechanical parameters conditions. The execution time of the ARO is less than 10 $\,\mu$ s.

Multi-Physics and Multi-Objective Optimization of a High Speed PMSM for High Performance Applications

High-speed permanent magnet synchronous machine (PMSM) can provide high power density and high efficiency, which is often highly desirable in high performance applications. A multi-physics optimization program based on the multi-objective genetic algorithm was developed in this paper, to achieve a tradeoff solution between the electromagnetic, mechanical, and thermal aspects. First, the parametric electromagnetic model was modeled based on the finite-element method, and then a thermal network model and an analytical mechanical model to determine the thickness of the magnet and the sleeve were developed and merged within a design cycle of the machine, in an effort to attain the target performances of 20 kW/kg at 20 000 r/min for a 2 MW PMSM. Optimization results indicated that a final design with eight poles and 48 slots could obtain a comprehensive performance between power density and efficiency, and the performance satisfied all the requirements.

Sensorless online measurements: application to variable speed drive systems

PurposeSensorless online measurements, application of variable speed drives has been given a great attention, especially over the past few years. In most of the previous literates dealing with permanent magnet synchronous motor (PMSM) drives, the combination of inter-sampled behavior with high gain design approach has not been discussed yet. This paper aims to discuss this feature in-depth.Design/methodology/approachThe study contains a different approach for an observer running with surface-mounted permanent magnet synchronous machine drives to implement sensorless control. Design of sampled data observer methodology for one kind of AC machine having non-linear model and backed by an elegant formal stability convergence analysis using the tools of Lyapunov stability techniques was highly recommended in scientific contributions, and it is yet needed to be solved.FindingsIn this study, a solution to observation problem is covered and developed by combining ideas from the high-gain design approach and inter-sample predictor based on stator voltage measurements. The output state currents are accessible only at the sampling instant to solve the problem of states observation at continuous-time mode. This allows to reducing the usage of online appliances, improving reliability of control design and saving costs.Practical implicationsThe proposed observer is capable of guaranteeing an acceptable closed loop dynamic response over a wide range of operation region and industrial process for random initial conditions.Originality/valueThe output state predictor has been interred in constructing the innovation correct term to prove the robustness of the proposed observer against attenuated sampling interval. To validate the theoretical results introduced by the main fundamental theorem and prove the observer stability convergence, the proposed observer is demonstrated through a sample study application to variable speed permanent magnet synchronous machine drive.

An iterative method for selecting decision variables in analytical optimization problem

In this paper, we present an iterative method to assist the designer in the setting of decision variables in an optimization problem with analytical models. This method is based on the Design Structure Matrix (DSM) which allows a clear representation of interactions between variables. Such a process becomes particularly useful for complex optimal design for which choosing the right decision variables to efficiently solve the problem is not so trivial. This approach is applied to the geometrical model of a High Speed Permanent Magnet Synchronous Machine (HSPMSM)

Fast iron losses model of stator taking into account the flux weakening mode for the optimal sizing of high speed permanent internal magnet synchronous machine

The optimal design of electrical machines is an important issue in automotive industry in order to reduce cost and volume of the actuator and improve its performances. In this context, the use of compact machines with high power density is preferred and consequently high speed machines where field weakening is required. In addition, a really optimal design requires to dispose sufficiently accurate models of main physical phenomena involved in electromechanical conversion. This models need to be sufficiently fast in order to be suitable with optimization process. An important limitation in the use of internal permanent magnet synchronous machine with distributed windings is temperatures insides the machine especially in the windings and thus the internal losses. At high speed with field weakening operation, iron losses, sensitive to flux densities variation in iron, could be really high because of the high electrical frequency linked to rotor speed and sharp variation of flux density waveforms inside the iron in stator due to the field weakening operation. This study, for the electric machine design, is based on the first harmonic hypothesis, i.e., without harmonic currents. An original and mathematical model has been developed and provides fast and accurate estimation of iron losses particularly in field weakening operation even with machine supplied by sinusoidal currents as described in this paper. It uses a polynomial form of iron losses in function of fundamental electrical frequency and take into account the flux density waveforms in yoke and teeth by use of nonlinear iron coefficients linked to id–iq currents. This paper will present the complete method calculating the iron coefficients from a nonlinear magnetic nodal network of the machine. A detailed study of local flux density waveform and harmonic content in yoke and teeth will be provided for two particular operating points: at maximal power without field weakening and at maximal power at maximal speed. These two points require accurate estimation in an optimal design of electrical machine. In addition, the local iron coefficients in teeth and yoke per volume unit will be provided in order to study the local evolution of iron losses in field weakening operation. It will show that iron losses do not follow the same evolution in the yoke and the teeth by the fact that the flux density distribution in teeth is more sensitive to the field weakening. An application of this model will be provided for the calculation of iron losses on whole operating space for a specific machine. A comparison will be provided between the fast model and finite elements approach.

Multi-level integrated optimal design for power systems of more electric aircraft

This paper proposes a multi-level optimal design method for a complex actuation system of more electric aircraft. The multi-level structure consists in sharing the optimization process in several levels, here 2, a “system level” which involves main coupling variables and a “component level” with one optimization loop for each device. The interest of this method is to separate the optimal design of each component, making easier the convergence of loops. This method is applied to a relatively complex power conversion system including a high speed permanent magnet synchronous machine (HSPMSM) supplied by a pulse width modulation (PWM) voltage source inverter (VSI) associated with a DC-link filter. Its interest is shown through a comparison with classical design approaches employed in previous works.

Research on the Torque and Back EMF Performance of a High Speed PMSM Used for Flywheel Energy Storage

Due to advantages such as high energy density, high power density, rapid charge and discharge, high cyclic-life, and environmentally friendly, flywheel energy storage systems (FESs) are widely used in various fields. However, the performance of FES systems depends on the performance of a high speed machine, therefore, the design and optimization of a high efficiency and high power density machine are very crucial to improve the performance of the whole FES system. In this paper, a high speed permanent-magnet synchronous machine (PMSM) is researched. Considering the requirement of low torque ripple in low speed and loss caused by back electromotive force (EMF) harmonics, the electromagnetic performance is improved from points of view of slot/pole matching, magnetic-pole embrace with the finite element method (FEM). Furthermore, the magnetic-pole eccentricity, the slot opening, the thickness of PM and air-gap length are also optimized with Taguchi method. The electromagnetic performance, such as torque ripple, cogging torque, average torque and back EMF wave are much improved after optimization. Finally, experiments are carried out to verify the calculated results.

Peak power bi-directional transfer from high speed flywheel to electrical regulated bus voltage system: a practical proposal for vehicular technology

This paper provides a design outline and implementation procedure for a secondary energy storage unit (SESU) that can be used to meet the peak energy requirements of an electric vehicle during both acceleration and regenerative braking. The life cycle of the electric vehicle's batteries can be extended considerably by supplying peak energy requirements from a secondary source. A simulation study was conducted to determine the peak power and energy requirements over the SAE recommended electric vehicle test procedure. A scaled prototype SESU was built using flywheel energy storage, and tests were performed to determine the energy transfer capabilities of a flywheel coupled high speed permanent magnet synchronous machine through the proposed system's energy storage tank. Results are presented that indicate the necessity of the energy storage tank. An evaluation of the proposed system is also included which indicates the practicality of the system when compared to conventional regenerative control techniques.